The present disclosure relates to controlling the infeed throat opening of a wood chipper that is used for processing brush and logs, and which has a sensor to sense when incoming dense material exceeds a selected height, and causing the feed throat to open momentarily in order to feed a log or other dense, solid material into a chipper rotor. As shown, an upper feed roller is raised to open the throat. After a timed interval the lifting force is released to permit the upper feed roller to bear against the material being fed with the normal spring force applied to the feed roller.
Various brush chippers have been advanced, and they generally have a powered chipper rotor that will disintegrate brush, logs or the like that are fed into a chipper rotor. Prior chippers have springs or actuators to provide a force bearing on incoming feed material, and have in some manner sensed the load on or speed of the rotor or chipper wheel and provided for various corrective action when the load exceeded a certain level. The sensors used may be sensing drive engine speed, hydraulic pressure, if the unit is driven with hydraulic motors, or other sensors that sense when the chipper disc or rotor starts to slow. In addition there are automatic reversing drives which will reverse the in-feed roller direction of rotation when the load on the chipper rotor exceeds a certain load level.
Additionally, many of the existing brush chippers have operator controls to permit the operator to manually move or raise an in-feed roller to accommodate large material that normally would not be fed because of the throat size of the in-feed passage.